Brienna Geology Blog

One metamorphic rock that is often used in construction is marble.  The parent rock of marble is limestone. It is medium to coarse grained, and is fairly soft, only being a 3 on Moh's hardness scale. However, since marble is made primarily of calcite, it is susceptible to chemical weathering by acid rain. This means that if the marble is exposed to the elements, it can erode and deteriorate quickly. There are sealants and other products available to protect from this though. It has many uses in construction. Marble can be used as the primary construction material in statues, monuments, and buildings. Some famous examples are the Lincoln Memorial, the Supreme Court building, the Taj Mahal. and the Washington Monument. It can also be used for more decorative/aesthetic purposes such as counter tops, shower walls, and staircases. I don't have marble counter tops or anything in my humble college apartment, but I'm pretty sure there is some being used in the Spori build...

 I decided to do my blog post on two different sedimentary rocks. This week has been slightly crazy, so I just snapped some pictures of some samples in the geology lab on campus, so I already knew they were sedimentary because of their labels. This first rock is rock gypsum. Rock gypsum is a chemical sedimentary rock. It is not very hard, being made of gypsum, with a hardness of 2. I was able to scratch this with my fingernail. It is nonclastic (has no clasts) and this sample didn't have any outstanding structures such as layers or ripples. Rock gypsum is formed in evaporating basins or playa lakes. It forms when gypsum precipitates from concentrated solutions and can be used in plaster. The second sedimentary rock I took pictures of was a sample of shale. Shale is formed when clay deposits get compacted. This rock has clay-sized clasts, but they are so tiny you cannot see them without a really good magnifier. (We couldn't see the clasts in lab.) The clasts are well sor...

The video I found is of Mount Tavurvur erupting in 2014. The eruption captured in this video is an explosive one. The lava is not just flowing out, there is some pressure built up which leads to the explosion. The video also captures the sound burst which I thought was very cool.  Mount Tavurvur is an active volcano in Papua New Guinea and is considered to be quite dangerous. It is a cinder cone. I think it is fairly new, but I am unsure and couldn't find the age of it. Cinder cones are built from ejected lava fragments that begin to harden in flight. It is relatively small at a height of 223 meters, with steep sides and a characteristic crater. (Map from http://www.dailymail.co.uk/sciencetech/article-2747577/Holy-smokes-Watch-explosive-moment-volcano-erupts-triggers-SONIC-BOOM-sending-shockwaves-sky.html) from https://www.washingtonpost.com/news/capital-weather-gang/wp/2014/09/03/ nasa-satellite-captures-incredible-extent-of-tavurvur-volcano-ashfall/ T...

I went and walked around for a couple hours around Rexburg and couldn't really identify any minerals, so I decided to go back to my roots.I'm from a little town called Dubois. Not too far north is an opal mine in Spencer, Idaho.  Opal is a silicate mineral and can form in all rock environments, especially in igneous environments. It is a precious gemstone and can be quite expensive to buy. It can be identified by it's luster, streak, and darkening in heat. Here are some facts about opal: Chemical composition: S iO 2 · n H 2 O. Color: c olorless, white, yellow, red, orange, green, brown, black, blue, pink Streak: white Luster: subvitreous to waxy Hardness: 5.5-6 Specific Gravity: 2.15 Fracture: conchoidal to uneven Cleavage: none Diagnostic Feature: darkens upon heating The cool thing about this opal mine is that the public can go mine for just $15. You can stay as long as you like and can bring out a pound of rocks. I've seen some pretty cool opa...

"Odd New Theory Explains How Early Earth Got Its Oxygen" Cyanobacteria diagram from https://en.wikipedia.org/wiki/Cyanobacteri a Oxygen production on Earth is theorized to have started about 2.5 billion years ago by oceanic cyanobacteria. These cyanobacteria produced oxygen as a product of photosynthesis. At around 2.3 billion years ago, an environmental change occurred, called the Great Oxygenation Event (GOE). At this point, the oxygen sinks on Earth became saturated, so oxygen produced by these cyanobacteria was free to go into the atmosphere. But what happened during that in between period? There are many theories that explain what happened in that time lag in between the beginning of oxygen production and the GOE. A more recent one is addressed in the news article I found. Convergent Boundary from https://geomaps.wr.usgs.gov/parks/pltec/converge.html According to a news article on Live Science, a new study by Megan Duncan and Rajdeep Dasgupta at Rice...

From the places we go, to the food we eat, to the cars we drive and the products we use, geology surrounds us. It's easy to forget how much we depend on the geological processes of the Earth. Idaho in particular is a geological hotspot (figuratively speaking). Not too far from Rexburg, we have the Menan Buttes, two of the largest volcanic tuff cones. This an amazing piece of geologic history that we are welcomed to explore and observe exposed igneous rock, such as obsedian. We are also close to Yellowstone, City of Rocks, the Tetons, and many other cool places to explore geology. We are even fairly close to the Rockies where the continental crust can be up to 70 kilometers (45 miles) thick!   (Image from hike at Menan Butte) Along with that Rexburg is a large farming community. In order to have a successful crops, farmers have to analyze the soil content, determine what minerals go in their fertilizer. The minerals in the soil will depend on what kind of rock it originat...